Behind a Mask of Sugar, a New Battle Front—Targeting Bacteria Associated with Antibiotic Resistance by Spoofing Sugar Signatures

Justin Ragains, associate professor at the LSU Department of Chemistry, recently received $430,960 from the National Institutes of Health to work on a vaccine to prevent infections caused by Acinetobacter baumannii, a species of bacteria associated with antibiotic resistance:

Acinetobacter baumannii

Acinetobacter baumannii

“In a nutshell, this project involves synthetic chemistry to generate vaccines. The specific bacteria we’re looking at is Acinetobacter baumannii, which is an important pathogen that tends to plague people with traumatic injury and compromised immune systems, such as patients in intensive care units or soldiers who’ve just returned with wounds from combat—anyone who’s not 100 percent to begin with could be vulnerable to this bug. We see more and more strains that are multi-drug resistant, too, and even some that aren’t susceptible to a single drug on the market. So, there’s an urgent need for alternatives to antibiotics, and that’s where vaccines can come to the rescue.

“Our idea is to do something a little bit different than what other people who work on vaccines have typically done. We’re looking at a specific set of sugars on the surface of these bacteria called lipooligosaccharides, a molecular signature of sorts. While the bacteria use these to their own advantage, there’s plenty of evidence that our immune systems recognize them as antigens, which are substances capable of stimulating an immune response [triggering the production of antibodies].

“We’re right at the beginning of this three-year project. This is a laborious area of research, and development of vaccines is something that typically takes years or decades and a lot of money. So, future funding is something that’s almost certainly a necessity to keep this work going. Right now, baby steps. Once we’ve synthesized these antigens, we’ll team up with our very capable collaborators at the LSU School of Veterinary Medicine and perform a series of biological assays to see whether or not they hold promise.

“Vaccines based on sugars may seem strange as we’re used to thinking of sugars as something we metabolize and turn into energy, but sugars are ubiquitous in nature and serve all kinds of purposes. For example, wood is almost entirely made up of sugars, and the surfaces of all of the cells in your body and all of the cells elsewhere in the plant and animal kingdom are covered with them. This sugar coating is very important for cell-to-cell communication and signaling.

“I would have liked to be the person who came up with the concept of looking at sugars on the surface of bacteria as immunological targets, but the original work goes back to the early 20th century. Because of the development of effective antibiotics like penicillin, however, the idea fell out of vogue. But, since the 1980s or so, the idea has slowly come back into fashion because people realize that antibiotics alone will not solve the problems posed by infectious diseases caused by bacteria. When antibiotics first came, a lot of people thought, ‘So, this problem is solved,’ but as we know now, it is not.”


Elsa Hahne
LSU Office of Research & Economic Development